Heating glass and manufacturing method thereof

ABSTRACT

The present invention provides a heating glass including a glass; a transparent conductive oxide (TCO) layer formed on one surface of the glass; and a thermal conductive pattern formed on the transparent conductive oxide layer, and a method of manufacturing the same.

TECHNICAL FIELD

The present invention relates to a heating glass and a method ofmanufacturing the same, and more particularly, to a heating glass havingexcellent heating performance at a low voltage and exhibiting uniformheating performance to an entire area of glass so that a thermalconductive pattern is not well visible and frost and dew condensationare easily removed, and a method of manufacturing the same. Thisapplication claims priority from Korean Patent Application No.10-2010-0002494 filed on Jan. 12, 2010, in the KIPO, the disclosure ofwhich is incorporated herein by reference in its entirety.

BACKGROUND ART

During the winter or on a rainy day, frost is formed on a glass surfaceof a vehicle because of a difference between temperatures of the outsideand inside of the vehicle. In addition, in the case of an indoor skiresort, a freezing phenomenon occurs because of a difference betweentemperatures of the inside where there is a slope and the outside of theslope. Heating glass has been developed in order to solve the problem.The glass is a concept that after a thermal conductive pattern sheet isattached to a surface of glass or a thermal conductive pattern isdirectly formed on the surface of glass, heat is generated from thethermal conductive pattern by applying electricity to both terminals ofthe thermal conductive pattern, thus increasing a temperature of thesurface of glass. It is important for the heating glass for vehicles orbuildings to have low resistance in order to smoothly generate heat,and, more importantly, the heating glass should not be unpleasant to thehuman eyes. Accordingly, a known heating glass is manufactured throughITO (indium tin oxide) sputtering. In another method, a fine patternthat cannot be recognized by a person is manufactured on a surface ofglass by a photolithography manner. However, since a manufacturingprocess is complicated and a material is seriously wasted in theaforementioned method, the glass cannot be manufactured at low cost,thus hindering generalization of the heating glass.

Further, in the case of glass on which TCO (transparent conductiveoxide) such as ITO (indium tin oxide) is deposited, there is a problemin that heating performance suitable to remove frost and dewcondensation at a low voltage is not implemented.

DISCLOSURE Technical Problem

The present invention has been made in an effort to provide a heatingglass having excellent heating performance at a low voltage andexhibiting uniform heating performance to an entire area of glass sothat a thermal conductive pattern is not well visible, an infrared ray(IR) blocking function is ensured, and frost and dew condensation areeasily removed, and a method of manufacturing the same.

Technical Solution

An exemplary embodiment of the present invention provides a heatingglass including: a glass; a transparent conductive oxide (TCO) layerformed on one surface of the glass; and a thermal conductive patternformed on the transparent conductive oxide layer.

Another exemplary embodiment of the present invention provides a heatingglass laminate including: a glass; a transparent conductive oxide (TCO)layer formed on one surface of the glass; a thermal conductive patternformed on the transparent conductive oxide layer; an attachment filmprovided on a surface of the glass, on which the thermal conductivepattern is formed; and a glass provided on the attachment film.

Yet another exemplary embodiment of the present invention provides amethod of manufacturing a heating glass, including: a) printing a pasteincluding a thermal conductive material on one surface of a glass, onwhich a transparent conductive oxide layer is formed, by a printingmethod, and b) forming a thermal conductive pattern by firing theprinted paste including the thermal conductive material.

Still another exemplary embodiment of the present invention provides amethod of manufacturing a heating glass laminate, including: a) printinga paste including a thermal conductive material on one surface of aglass, on which a transparent conductive oxide layer is formed, by aprinting method, b) forming a thermal conductive pattern by firing theprinted paste including the thermal conductive material, and c)performing bonding by sequentially laminating an attachment film and theglass on a surface of glass, on which the thermal conductive pattern isformed.

Advantageous Effects

According to the exemplary embodiments of the present invention, thereare provided a heating glass having excellent heating performance at alow voltage and exhibiting uniform heating performance to an entire areaof glass so that a thermal conductive pattern is not well visible, aninfrared ray (IR) blocking function is ensured, and frost and dewcondensation are easily removed, and a method of manufacturing the same.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a mimetic diagram illustrating an offset printing process.

FIG. 2 illustrates an example of heating glass for vehicles.

FIG. 3 is a graph illustrating transmittance according to a wavelengthrange of heating glass manufactured according to Example 1 of thepresent invention.

FIG. 4 is a graph illustrating transmittance according to a wavelengthrange of heating glass manufactured according to Comparative Example 2.

BEST MODE

A heating glass according to the present invention includes a glass; atransparent conductive oxide layer formed on one surface of the glass;and a thermal conductive pattern formed on the transparent conductiveoxide layer.

The heating glass according to the present invention is characterized inthat the thermal conductive pattern is formed on the transparentconductive oxide layer formed on one surface of the glass. In the caseof the glass including only the transparent conductive oxide layer onthe surface thereof, heating performance suitable to remove frost anddew condensation at a low voltage is not exhibited. However, in thepresent invention, since the thermal conductive pattern is provided onthe transparent conductive oxide (TCO) layer formed on one surface ofthe glass, it is possible to provide the heating glass where the patternis not visible and heating performance is excellent even at a lowvoltage. Particularly, in the present invention, transmittance of IRrays may be reduced while transmittance of visible rays is maximized byusing the transparent conductive oxide layer and the thermal conductivepattern having a predetermined line width simultaneously.

Fluorine tin oxide (FTO), indium tin oxide (ITO) or AZO or GZO includingzinc oxide (ZnO), and aluminum (Al) or gallium (Ga) used as a dopant maybe used as the transparent conductive oxide, but the transparentconductive oxide is not limited thereto.

It is preferable that the thickness of the transparent conductive oxidelayer be 0.01 to 10 μm.

In the case where the thickness of the transparent conductive oxidelayer is less than 0.01 μm, sufficient conductivity is not ensured, andin the case where the thickness is more than 10 μm, transmittance may bereduced.

The transparent conductive oxide has a band gap of 3.5 eV or more.Further, if free electron density has a value of a predetermined levelor more, the wavelength of a visible ray region may pass therethroughand the wavelength of a long wavelength region may reflect thereon.Thereby, an excellent field of vision is ensured by passing of visiblerays, and transmittance of IR rays may be reduced.

The thermal conductive pattern may be formed by a printing method.

The thermal conductive pattern formed by the printing method mayslightly vary according to the kind of the paste or the printing method,but the surface thereof may be rounded by surface tension of the pasteincluding the thermal conductive material. This surface shape cannot beformed by a known photolithography method.

The vertical cross section of the rounded thermal conductive pattern mayhave a lenticular lens shape. The angle between the tangential line at acontact point of the thermal conductive pattern and the surface of thetransparent conductive oxide layer, and the surface of the transparentconductive oxide layer is 80° or less, preferably 75° or less and morepreferably 60° or less. It is preferable that the straight line area inthe rounded upper surface of the vertical cross section of the thermalconductive pattern be 1/50 or less in a circumference direction.

The line width of the thermal conductive pattern may be 100 μm or lessand preferably 0.1 to 30 μm. The interval between the lines of thethermal conductive pattern may be 200 μm to 30 mm.

In the present invention, it is possible to improve heating performanceand maximize transmittance of visible rays by forming the thermalconductive pattern having the line width of 100 μm or less andpreferably 30 μm or less on the aforementioned transparent conductiveoxide layer. Particularly, since the thermal conductive pattern havingthe aforementioned line width hardly blocks visible rays passing throughthe transparent conductive oxide layer, the field of vision may not bedisturbed.

The heating glass according to the present invention may have physicalproperties of transmittance of visible rays of 90% or more andtransmittance of IR rays of 50% or less at a wavelength of 2 micrometersor more by the aforementioned constitution. Further, the heating glassaccording to the present invention may have an excellent heatingproperty while having the aforementioned transmittances of visible raysand IR rays. For example, when the line width of the thermal conductivepattern is 20 micrometers and the line height thereof is 1.5micrometers, a heating value may be 200 to 400 W/m² at 10 V in the sizeof the front window of the actual vehicle. As described above since theheating glass according to the present invention exhibits the excellentheating property, the heating glass may be implemented at a low voltage.

Generally, the opening ratio of the pattern is reduced as the line widthis increased and the interval between the lines is reduced, andtransmittance of visible rays is reduced as the opening ratio isreduced. Meanwhile, since resistance is reduced under the condition ofreduction of transmittance of visible rays, the heating value isincreased as transmittance of visible rays is reduced. However, in thepresent invention, transmittance of visible rays is increased bycontrolling the line width and the interval between the lines asdescribed above, and low transmittance of IR rays and the excellentheating property may be exhibited by using the transparent conductiveoxide layer and the thermal conductive pattern together.

The height of the line of the thermal conductive pattern from thesurface of the transparent conductive oxide layer may be 1 to 100 μm.Preferably, the height is about 10 μm.

In the case where the numerical values of the thermal conductive patternare less than the aforementioned range, sufficient heating performancecannot be obtained.

The thermal conductive pattern may have a stripe, diamond, squarelattice, or circle form, but is not limited thereto.

For example, when the fluorine tin oxide layer is deposited in athickness of about 1 μm or less on the glass having the size of 1 m²,the heating performance of the heating glass is about 700 W/m² at 110 V.However, in the present invention, the heating value of about 400 W/m²may be implemented at a low voltage of about 10 V by forming the thermalconductive pattern on the fluorine tin oxide layer deposited on onesurface of the glass.

Examples of the thermal conductive material for forming the thermalconductive pattern may include copper or silver.

The heating glass according to the present invention may be connected tothe power for heating, and in this case, the heating value is 100 to 500W and preferably 200 to 300 W per m². Since the heating glass accordingto the present invention has the excellent heating performance even atthe low voltage, for example, 30 V or less and preferably 20 V or less,the heating glass may be usefully used in vehicles and the like. Theresistance of the heating glass is 5 ohm/square or less, preferably 1ohm/square or less, and more preferably 0.3 ohm/square or less.

The heating glass according to the present invention may have a shape ofcurved surface.

A heating glass laminate according to the present invention may includea glass; a transparent conductive oxide layer formed on one surface ofthe glass; a thermal conductive pattern formed on the transparentconductive oxide layer; an attachment film provided on a surface of theglass, on which the thermal conductive pattern is formed; and a glassprovided on the attachment film. Since all contents described in theheating glass are applied thereto, a detailed description thereof willbe omitted. The heating glass laminate according to the presentinvention may have a shape of curved surface.

FIG. 2 illustrates the detailed embodiment of the heating glass forvehicles. If the thermal conductive pattern having the line width of 20μm and the height of 1.5 μm is formed as shown in FIG. 2 assuming thatthe heating value required in the vehicle is 200 to 300 W, when threethermal conductive patterns per 1 mm, that is, the thermal conductivepatterns having the pitch of about 330 μm, are formed, desiredperformance is implemented. In this case, the opening ratio is310/330=93.9%, which is suitable to be used for vehicles. In addition,in the case where specific resistance of the thermal conductive patternmaterial is two times higher, if the pitch is set to 165 μm, the openingratio is 87.8% while the same heating value is obtained, whichcorresponds to transmittance suitable to be used for vehicles.

The heating glass having the stripe shape according to FIG. 2 has thefollowing physical properties.

R(Ω)=ρ×(L ₁ /nA)=ρ×(L ₁×ρ)/(L ₂ ×w×h)

Ar(%)=(1−w/p)×100

R: Resistance between bus bars

Ar: Opening ratio

ρ: Specific resistance of the thermal conductive pattern (Ω·cm)

L₁: Interval between bus bars (cm)

n: Number of thermal conductive patterns

A: Cross-sectional area of the conductive line (cm²)

p: Interval between lines of thermal conductive patterns (cm)

L₂: Length of the bus bar (cm)

w: Width of the thermal conductive pattern (cm)

h: Height of the thermal conductive pattern (cm)

That is, in the case where the line width w of the thermal conductivepattern is 20 μm, the height h is 1.5 μm, specific resistance p is3×10⁻⁶ Ω·cm, the interval p between the lines of the thermal conductivepattern is 300 μm, L₁ is 1 m, and L₂ is 1 m, R is 0.3Ω and the openingratio is 93.3%, and in this case, if 12 V is applied to both terminalsthereof, heating of 480 W is obtained.

A method of manufacturing a heating glass according to the presentinvention may include a) printing a paste including a thermal conductivematerial on one surface of a glass, on which a transparent conductiveoxide layer is formed, by a printing method, and b) forming a thermalconductive pattern by firing the printed paste including the thermalconductive material.

In the case of the glass used in step a), the glass including thetransparent conductive oxide layer manufactured in advance may be usedin step a), or the glass may be used in step a) after performing inadvance the step of preparing the glass on which the transparentconductive oxide layer is formed by forming the transparent conductiveoxide on one surface of the glass prior to step a). Examples of a methodof forming the transparent conductive oxide layer on one surface of theglass may include a sputtering method and an atmospheric pressurechemical vapor deposition (AP CVD) method.

In step a), the paste including the thermal conductive material isprinted on one surface of the glass, on which the transparent conductiveoxide layer is formed, by the printing method. A method of forming athermal conductive pattern of a heating glass by a photolithographymanner is known in the related art, but a manufacturing process iscomplicated and a high cost is required in this manner. However, in thepresent invention, a relatively low cost may be required, amanufacturing process may be simple, and a precise thermal conductivepattern having the small line width may be formed by forming the pastefor forming the thermal conductive pattern by the printing method.

The printing method is not particularly limited, and a printing methodsuch as offset printing, screen printing, and gravure printing may beused. For example, the offset printing may be performed by using themethod in which after the paste is filled in the intaglio on which thepattern is formed, first transferring is performed by using siliconrubber that is called the blanket, and second transferring is performedby bringing the blanket and glass close contact with each other, but isnot limited thereto.

Most of the paste is transferred on glass because of the releaseproperty of the blanket, and as a result, a separate blanket washingprocess is not required. The intaglio may be manufactured by preciselyetching the soda lime glass on which the desired thermal conductivepattern is formed, and metal or DLC (diamond-like carbon) coating may beperformed on the surface of glass for the durability. The intaglio maybe manufactured by etching the metal plate.

In the present invention, it is most preferable to use the offsetprinting method in order to implement the more precise thermalconductive pattern. FIG. 1 illustrates the offset printing method.According to FIG. 1, after the paste is filled in the pattern of theintaglio by using a doctor blade in a first step, the first transferringis performed by rotating the blanket, and the second transferring isperformed on the surface of glass by rotating the blanket in a secondstep.

Metal having excellent thermal conductivity is preferably used as thethermal conductive material of step a), copper, silver and the like maybe used, and silver is most preferable. In the present invention, thethermal conductive material may be used in a particle form.

The paste of step a) may further include an organic binder in additionto the aforementioned thermal conductive material so that the printingprocess is easily performed. It is preferable that the organic binderhave a volatile property in the firing process. In addition, the pastemay further include a glass frit in order to improve the attachmentstrength of the paste to glass. If necessary, a solvent may be furtheradded.

The paste of step a) may be printed so that the line width of theprinting pattern line after the firing is 100 μm or less and preferably0.1 to 30 μm or less, may be printed so that the interval between theprinting pattern lines after the firing is 200 μm to 30 mm, and may beprinted so that the height of the line from the surface of thetransparent conductive oxide layer is 1 to 100 μm.

The printing pattern printed in step a) may have a diamond, rectangularlattice or circle form in addition to the stripe shown in FIG. 2, and isnot limited to a specific form. It is preferable that the opening ratioin the printing pattern, that is, a ratio of a region of the glass notcovered by the printing pattern, be 70% or more.

For example, the thermal conductive pattern of step b) may be a gridtype pattern having a line width of 20 μm and an interval between linesof 280 μm, and heating performance of the pattern may be about 500 W/m².

If the aforementioned paste is printed in a predetermined pattern onglass by using the printing method and then subjected to the firingprocess of step b), a pattern having thermal conductivity is formed. Inthis case, a firing temperature is not particularly limited, but may be400 to 700° C. and preferably 500 to 650° C. If necessary, the glass maybe shaped so as to correspond to the purpose such as buildings orvehicles in the firing step. For example, the glass may be shaped likeglass having a curved surface of a vehicle in the firing step.

Further, a method of manufacturing a heating glass laminate according tothe present invention may include a) printing a paste including athermal conductive material on one surface of a glass, on which atransparent conductive oxide layer is formed, by a printing method, b)forming a thermal conductive pattern by firing the printed pasteincluding the thermal conductive material, and c) performing bonding bysequentially laminating an attachment film and the glass on the surfaceof the glass, on which the thermal conductive pattern is formed. Sinceall contents described in the method of manufacturing the heating glassare applied thereto, a detailed description thereof will be omitted.

The attachment film is not particularly limited as long as the film isused in the art, and, for example, a PVB film or an EVA film may beused. The PVB film is not particularly limited, but it is preferablethat the thickness thereof be 350 to 450 μm.

The glass bonded to the attachment film may be formed of only glass andmay be formed of glass that is provided with the thermal conductivepattern manufactured as described above.

If necessary, prior to the bonding step, a step of forming an electrodeconnected to the thermal conductive pattern may be further included.

In step c), a method known in the art may be used as the bonding method.

MODE FOR INVENTION

Hereinafter, the present invention will be described in more detailthrough Examples.

Example 1

The FTO glass (surface resistance: 15 Ω/square), on a surface of whichthe fluorine tin oxide layer was formed, was prepared. Further, thesilver paste was prepared by dissolving 80% of silver particles havingthe particle diameter of 2 μm, 5% of polyester resin, and 5% of glassfrit in 10% BCA (butyl carbitol acetate) solvent.

In addition, the glass having the grid type pattern formed to have theinterval of 300 μm, the width of 20 μm, and the depth of 10 μm and havethe right angle was prepared as the flat plate for printing.

Next, the grid type silver thermal conductive pattern was formed on thesurface of the FTO glass FTO layer by using the offset printer, and thenfired at 650° C. for 3 min to form the silver thermal conductivepattern. In this case, the interval between the lines of the formedsilver thermal conductive pattern was 300 μm, the line width was 25 μm,the height of the line was 1.5 μm, and the opening ratio was 84%.

Comparative Example 1

The FTO glass heating glass (surface resistance: 15 Ω/square), on asurface of which the fluorine tin oxide layer was formed, was prepared.

Comparative Example 2

After the grid type silver thermal conductive pattern was formed on thesurface of the glass by using the silver paste manufactured in Example 1by the offset printer, firing was performed at 650° C. for 3 min to formthe silver thermal conductive pattern. In this case, the intervalbetween the lines of the formed silver thermal conductive pattern was300 μm, the line width was 25 μm, the height of the line was 1.5 μm, andthe opening ratio was 84%.

Experimental Example Driving Voltage

The bus bar was formed by bringing the copper strip into contact withthe heating glass manufactured in Example 1 and Comparative Example 1 byusing the clip. Thereafter, the voltage when the heating glass had theheating value of 400 W/cm² was measured, and is described in thefollowing Table 1.

TABLE 1 Voltage when a heating value is 400 W/cm² Example 1 10 VComparative Example 1 75 V

As shown in the aforementioned result, it can be seen that the heatingglass according to the present invention exhibits the high heating valueeven at a low voltage.

IR Blocking Test

Transmittances of the heating glass manufactured in Example 1 andComparative Example 2 were measured by using the spectrometer in awavelength region of 300 to 2500 nm, and the results are shown in FIGS.3 and 4.

As shown in the results, it can be seen that transmittance of theheating glass according to the present invention is reduced in theregion of 900 nm or more, but transmittance of the heating glassaccording to Comparative Example 2 is high for the entire region.

1. A heating glass comprising: a glass; a transparent conductive oxide(TCO) layer formed on one surface of the glass; and a thermal conductivepattern formed on the transparent conductive oxide layer.
 2. The heatingglass of claim 1, wherein the transparent conductive oxide is fluorinetin oxide (FTO), indium tin oxide (ITO) or AZO or GZO including zincoxide (ZnO), and aluminum (Al) or gallium (Ga) used as a dopant.
 3. Theheating glass of claim 1, wherein a thickness of the transparentconductive oxide layer is 0.01 to 10 μm.
 4. The heating glass of claim1, wherein the thermal conductive pattern is formed by a printingmethod.
 5. The heating glass of claim 1, wherein a line width of thethermal conductive pattern is 100 μm or less, an interval between linesis 200 μm to 300 mm, and a height is 1 to 100 μm from a surface of thetransparent conductive oxide layer.
 6. The heating glass of claim 1,wherein the thermal conductive pattern includes copper or silver.
 7. Theheating glass of claim 1, further comprising: an attachment filmprovided on a surface of the glass, on which the thermal conductivepattern is formed; and a glass provided on the attachment film.
 8. Theheating glass of claim 1, wherein transmittance of a visible ray is 90%or more and transmittance of an infrared ray is 50% or less at awavelength of 2 micrometers or more.
 9. A method of manufacturing aheating glass, comprising: a) printing a paste including a thermalconductive material on one surface of a glass, on which a transparentconductive oxide layer is formed, by a printing method, and b) forming athermal conductive pattern by firing the printed paste including thethermal conductive material.
 10. The method of manufacturing a heatingglass of claim 9, comprising: before step a), preparing the glass, onone surface of which the transparent conductive oxide layer is formed,by forming the transparent conductive oxide layer on one surface of theglass.
 11. The method of manufacturing a heating glass of claim 9,wherein the transparent conductive oxide is fluorine tin oxide (FTO),indium tin oxide (ITO) or AZO or GZO including zinc oxide (ZnO), andaluminum (Al) or gallium (Ga) used as a dopant.
 12. The method ofmanufacturing a heating glass of claim 9, wherein a thickness of thetransparent conductive oxide layer is 0.01 to 10 μm.
 13. The method ofmanufacturing a heating glass of claim 9, wherein the printing method isoffset printing, screen printing or gravure printing.
 14. The method ofmanufacturing a heating glass of claim 9, wherein the thermal conductivematerial is copper or silver.
 15. The method of manufacturing a heatingglass of claim 9, wherein the paste further includes an organic binderand a glass fit.
 16. The method of manufacturing a heating glass ofclaim 9, wherein a line width of the thermal conductive pattern is 100μm or less, an interval between lines is 200 μm to 300 mm, and a heightis 1 to 100 μm from a surface of the transparent conductive oxide layer.17. The method of manufacturing a heating glass of claim 9, wherein theprinting is performed so that the paste is printed in a stripe, diamond,rectangular lattice or circle form.
 18. The method of manufacturing aheating glass of claim 9, further comprising: c) performing bonding bysequentially laminating an attachment film and the glass on the surfaceof the glass, on which the thermal conductive pattern is formed.
 19. Themethod of manufacturing a heating glass of claim 18, further comprising:before the bonding, forming an electrode connected to the thermalconductive pattern.